Research On Transmission Line Inspection Based On Four-rotor UAV

High-voltage transmission lines are exposed to the wild all the year round.Bad weather,bird nesting,artificial garbage and other factors will cause damage to the transmission line or pose a safety hazard.The safety and working efficiency of traditional artificial power inspection has not met the requirements,therefore,power inspection requires a better method.The multi-rotor drone's in-situ take-off,landing and fixed-point hovering characteristics can well meet the requirements of power inspection.When the four-rotor UAV performs power inspection,the UAV needs to have high-precision attitude calculation and certain anti-interference ability.At the same time,the drone needs high autonomy.It is necessary for UAV to process patrol images to determine whether there are problems in transmission lines.In this thesis,the attitude reconstruction algorithm is used to carry out the data fusion filtering of the inertial navigation device.The Kalman filter algorithm is used to improve the accuracy of the barometer and GPS.Autonomous power patrol flow of four-rotor UAV and image processing in patrol process are designed in this thsis.The specific content is as follows:(1)In this thesis,the Mahony algorithm and the gradient descent method are used to fuse the data of the inertial navigation device respectively,and the solution results of the two algorithms are compared.Finally,the gradient descent method is used to solve the attitude of the quadrotor UAV.The pedestal PID-ADRC controller is used to control the attitude of the drone.The outer ring adopts the angle PID controller,and the inner ring adopts the angular velocity auto disturbance rejection controller to enhance the anti-interference ability of the drone.(2)In this thesis,the Kalman filter algorithm is used to integrate the barometer,GPS and inertial navigation device.The measurement height of the barometer,the measurement position and velocity of the GPS is used as observations,and the position and velocity obtained by the accelerometer is used as state quantities.Kalman is used.The filtering algorithm fuses the state quantity and the observed data.In order to realize the autonomy of UAV power inspection,The autonomous take-off,route flight,automatic return and landing are also studied and designed in this thsis..(3)In this thesis,for the problem of self-explosion and damage of insulator strings,the image processing technology is used to process the aerial image,and the existing maximum inter-class variance method is improved,which reduces the calculation amount and improves the speed of threshold segmentation.The pixel-based detection method is designed to detect and locate the damaged insulator.Aiming at the problem of foreign objects hanging on the transmission line,the Hough transform is used to extract the characteristics of the transmission line in the aerial image,and the affine transformation is used to detect and locate the foreign objects on the transmission line.The above research scheme was verified on the built four-rotor UAV platform.The experimental data showed high accuracy of attitude calculation,strong anti-interference ability of the attitude controller,high positioning accuracy of height and horizontal position,damage of insulator and accurate detection of foreign objects in transmission line.